Microsoft advises administrators to patch Exchange servers
Microsoft advises users to maintain their Exchange servers’ security updates as well as take precautions to strengthen the environment, like turning on Windows Extended Protection and establishing certificate-based signing of PowerShell serialization payloads.
“It is critical to keep your Exchange servers updated. This means installing the latest available Cumulative Update (CU) and Security Update (SU) on all your Exchange servers (and in some cases, your Exchange Management Tools workstations), and occasionally performing manual tasks to harden the environment, such as enabling Extended Protection and enabling certificate signing of PowerShell serialization payloads.” Said the exchange team in a post.
“Attackers looking to exploit unpatched Exchange servers are not going to go away. There are too many aspects of unpatched on-premises Exchange environments that are valuable to bad actors looking to exfiltrate data or commit other malicious acts.”
The company urges to install the most recent supported CU (CU12 for Exchange Server 2019, CU23 for Exchange Server 2016, and CU23 for Exchange Server 2013 as of this writing) and the most recent SU to protect your Exchange servers from attacks that take use of known vulnerabilities (as of this writing, the January 2023 SU). You simply need to install the most recent version of the Exchange Server CU or SU because they are cumulative. Install the most recent CU before checking to see whether any SUs were published following the CU. Install the newest (latest) SU if that’s the case.
The vendor advises always running the Exchange Server Health Checker script after installing updates and claims that the Exchange server upgrade process is “straightforward”.
Source
https://thehackernews.com/2023/01/microsoft-urges-customers-to-secure-on.html
https://techcommunity.microsoft.com/t5/exchange-team-blog/protect-your-exchange-servers/ba-p/3726001
Recently
https://cyberlabsservices.com/microsoft-january-2023-patch-tuesday/
